Re: Different answers in mathematica and my calculator.

*To*: mathgroup at smc.vnet.net*Subject*: [mg125655] Re: Different answers in mathematica and my calculator.*From*: Nile <thrasher300 at gmail.com>*Date*: Mon, 26 Mar 2012 01:45:57 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Your answer was perfect, it's exactly what I was looking for. Thank you very much. > Am 19.03.2012 11:04, schrieb Nile: > > 4/(3Power[2(-2)+3, (3)^-1]) > > > > I get -(4/3) (-1)^(2/3) in Mathematica but only > -4/3 on my calculator. > > > powers with non-integer exponents are not unique in > the domain of > complex numbers. Try Root[]: > > 4/(3 Root[#^3 - (2 (-2) + 3) &, 1]) > > > > N[Sec[8/(8 Sqrt[2])]]/Degree to get Cos^-1 of 8/(8 > Sqrt[2]) and it gives me 75 deg instead of 45... > > > > I'm not sure what I'm doing wrong, I tried in > Wolfram Alpha and it gives me the same thing. > > I am afraid, you mixed the inverse function > cos^(-1)(x) with the > reciprocal (cos(x))^(-1). Use ArcCos and > FunctionExpand (the latter to > convert Degree to Pi/180): > > ArcCos[8/(8 Sqrt[2])]/Degree // FunctionExpand > > > > > Thank you. > > > > -Francis > > > >